Roller assembly for boat trailer

ABSTRACT

A roller assembly designed specifically to assist in the loading of straked, molded boat hulls onto a trailer. The roller assembly comprises a support bracket pivotable about a longitudinal axis along the trailer. The bracket supports a straight transverse axle having identical rolls mounted at opposite ends thereof. The spaced rolls are specially formed to accomodate the strakes of a boat hull. Each include a cylindrical portion and conical end surfaces. The difference in diameter between the rollers and the intermediate axle is greater than the protrusion of the strake on the hulls engaged by the rolls.

1 51 Sept. 26, 1972 United States Patent Calkins ROLLER ASSEMBLY FOR BOAT 2,729,321 1/1956 Morrison 193/35 R TRAILER 2,889,945 6/1959 Holsclaw .................l93/42 X [72] Inventor: Oscar Calkins, Spokane, wash 3,003,655 10/1961 Bennett.....................214/506 1731 Assignee: Calkins Manufacturing Company, Primary ExaminerAlbert .l. Makay Spokane, Wash.

Jan. 25, 1971 Attorney-Wells, St. John & Roberts [22] Filed:

ABSTRACT A roller assembly designed specifically to assist in the App]. No.2 109,325

loading of straked, molded boat hulls onto a trailer.

52 U.s.c1..................214/s4,193/35 R, 193/35 c, The roller assembly comprises a support bracket pivotable about a longitudinal axis along the trailer.

193/35 B .B60p 3/10 .214/84, 505, 506; 280/414 R;

The bracket supports a straight transverse axle having identical rolls mounted at opposite ends thereof. The spaced rolls are specially formed to accomodate the I[58] Field of Search....

193/42, 35 R, 35 A, 35 SS, 35 C, 35 TE, 35

strakes of a boat hull. Each mclude a cylindrical portion and conical end surfaces. The difference in diameter between the rollers and the intermediate axle is greater than the protrusion of the strake on the hulls F, 35 MD, 35 J, 35 G, 35 B, 35 s engaged by the rolls.

References Cited 9 UNITED STATES PATENTS 3,547,285 12/1970 Plummer.....................214/84 6 Claims, 6 Drawing Figures PATENTEDSEP26 x972 SHEET 2 OF 2 ROLLER ASSEMBLY FOR BOAT TRAILER BACKGROUND THE INVENTION The development of molded boat hulls, constructed of glass fiber reinforced resins has tended toward the hull configuration known generally as a deep-V hull. To overcome the tendency of such hulls to plow into water, longitudinal protruding ribs or strakes are molded along the hull exterior. Such strakes begin near the bow of the boat and spread transversely along the hull to a location approximately one-half the length of the hull. The strakes and hull design remain substantially constant throughout the remainder of the hull to the transom. The longitudinal protrusion of the strakes assists in lifting the hull and trap air beneath their surfaces to reduce the frictional drag on the hull exterior.

The accomodations of boat trailers to straked hulls has posed continual difficulty in the boat trailer industry. The protruding strakes have a tendency to exert substantial transverse forces on rolls engaged thereby,

and often wedge against the rolls at one side of the boat to shift the keel of the boat from its proper central position along the keel rolls of the trailer. This problem is greatest with respect to the transom rolls on a trailer, which must engage the straked portions of the hull prior to substantial engagement of the central keel by the keel rolls. The transom rolls must be therefore overcome the forces exerted by the strakes without the assistance of substantial counteracting forces which are progressively applied to the boat keel travels forward along the central keel rolls.

The present roller apparatus is particularly adapted to ride along and over the projecting strakes as a boat hull is engaged thereby. The individual roller assemblies, which are mounted to opposite sides of the trailer centerline, each include a supporting bracket restricted to pivotal movement in a longitudinal plane and spaced rolls at each end of a transverse axis. The rolls are restricted to rotational movement along the common axis of the axle and are each shaped with conical end surfaces capable of frictionally engaging the outer hull surfaces and rolling across the strake as the strake moves longitudinally along the trailer. All metal parts are protected so as to eliminate accidental damage to a boat hull by engagementof the assembly.

SUMMARY OF THE INVENTION The invention described in the following specification relates to a novel roller assembly, used in combination with a boat trailer for support of the sides of a molded boat hull having protruding longitudinal strakes formed on its exterior. The roller assembly comprises a transverse supporting bracket with hearing means for pivotally connecting the bracket to a supporting trailer member along a longitudinal axis. A straight axle extends transversely across the bracket and carries a pair .of oppositely facing rollers at its respective ends. The rolls are mounted about rotational axes coincident with the axle axis. Each roller includes a center cylindrical section and symmetrical tapered end surfaces in the form of conical surfaces centered along the roller rotational axis. The rolls are spaced by a distance sufficient to accomodate at least one strake. The difference in diameter between the enlarged rolls and the diameter of the axle is greater than the projection of the strake outward of the boat hull.

It is a first object of this invention to provide a protective roller assembly for a boat trailer wherein the roll is capable of being traversed by longitudinal strakes during movement of the boat hull over the rolls.

Another object of the invention is to provide a fully protected roll which cannot itself be damaged by engagement with a boat hull and wherein no outer cover can be forced from the roll due to the forces resulting from strake engagement.

Another object of the invention is to provide an improved roller assembly which is adaptable to various types and sizes of boat trailers without substantial modification.

DESCRIPTION or THE DRAWINGS FIG. 1 is a rear perspective view of a boat trailer equipped with the present roller apparatus;

FIG. 2 is an enlarged rear elevation view of a single roller assembly;

FIG. 3 is an elevational section view taken along a transverse plane immediately forward'of the roller assembly;- I

FIG. 4 is a bottom view of the assembly seen in FIG.

' DESCRIPTION OF THE PREFERRED EMBODIMENT The present roller assembly is adapted for use on a boat trailer, being designed specifically to facilitate engagement of boat hulls having longitudinal strakes along the lower portions thereof. The roller assembly might be used on many various types of boat trailers. For illustration purposes, it is shown in FIG. 1 as mounted on a trailer of the type shown in my U. S. Pat. No. 3,512,667, granted May 19, I970.

The precise details of the trailer are not necessary to a full understanding of the present invention. However, the trailer generally comprises a longitudinal rigid framework 10 supported by wheels 11. A forwardly extending tongue 12 is mounted along the centerline of 'the trailer. The trailer components are symmetrical about a longitudinal center line drawn through the tongue 12. Side channels 13 extend rearwardly along the trailer.

The trailer includes a forward keel roll 14, which is stationary and a conventional winch assembly 15 at the forward end of tongue 12. The bow of a boat is engaged by a rope or cable and pulled forwardly over the trailer framework 10 by normal operation of the winch assembly 15.

At the rear of the trailer is a rear hull engaging means that is self-centering to proportionally support the rear of the boat at the keel and transom. This includes a rigid cradle frame 16 pivotally mounted to the framework 10 about a transverse axis at its center. The cradle 16 is substantially U-shaped, with its open end facing rearwardly. At its forward end it mounts a keel roll 17. The open rear ends of the cradle frame 16 mount identical transom roller assemblies 18, which are the subject matter of the present disclosure and which are described in detail below.

The trailer illustrated also includes a self-adjusting front hull engaging means in the form of a shortened U- shaped cradle frame 20 pivotally mounted to framework about a second intermediate transverse axis. The forward end of cradle frame carries a keel roll 21. The open rear end of cradle frame 20 pivotally supports chine roller assemblies 22, which are also detailed below. A plurality of intermediate cradle frames 20 and additional forward keel rolls 14 can be provided in a trailer assembly, depending upon the size of the trailer and the size and weight of the boat to be transported thereon.

In general, the boat trailer is used to load or unload a boat by control of winch assembly 15. When loading a boat, it is pulled forwardly over the transom roller assembly 18, which centers the bow of the boat and engages the hull, which is subsequently pulled over the keel roll 17. As the boat moves forward, the cradle frame 16 pivots relative to framework 10 to accomodate the hull configuration and weight distribution. A similar action occurs as the hull "is pulled over the cradle frame 20. The boat is securely located by the various cooperating rollers.

One difficulty involved in engaging the hull of molded boats today is the common provision of protruding longitudinal strakes along the roller sides of the hull. Such strakes tend to wedge against rollers and sometimes the transverse resulting forces are such as to push the boat to one side or the other of the centerline of the framework 10. This tendency has been eliminated by use of the transom roller assembly 18 and chine roller assembly 22 shown in FIG. 1.

These details of the single transom roller assembly 18 are illustrated in FIGS. 2-5. Each roller assembly is mounted on a rigid structural bracket 23 which extends transversely relative to the centerline of framework 10. Bracket 23 fixedly carries a transverse straight axle along its upper surface, the axle 24 being fixed to upstanding ears 25 at the respective ends of brackets 23. The respective ends of axle 24 protrude outwardly beyond the ends of brackets 23. A pair of identical rolls 26 are rotatably mounted at the respective ends of each axle 24 by interior bushings recessed within the roll 26.

Each roll 26 is therefore rotatably mounted about the center axis of the axle 24 on which it is mounted. The outer end of axle 24 is recessed inwardly of roll 26 to eliminate any possible projection of a rigid metal element at the outer ends of the rolls 26.

Each roll 26 comprises a large diameter rubber roller formed about a center bushing or bearing sleeve, which in turn is rotatably mounted on the axle 24. The central portion of each roll 26 is cylindrical in shape, being centered about the axis of its axle 24. The respective ends of each roll 26 are tapered in a conical configuration, leading outwardly fromthe cylindrical surface and terminating slightly outward of the diameter of axle 24. The difference in radius between the rolls 26 and axle 24 is greater than the projection of strakes along a boat hull, so that strakes can be accornodated between the paired rolls 26 without engaging axle 24. For further protection the axle 24 is preferably 'coated with a resilient protective material intermediate the rolls 26. This coating may be a coating of rubber or suitable resin, such as polyvinyl chloride.

The rolls 26 are preferably manufactured from hard rubber capable of lifting the boat hull under the loading forces exerted due to weight of the boat. Rubber having a rating of in a Durometer test has been found to be very suitable for this purpose. However, the rolls 26 might be made of any material havingssuitable frictional and load supporting capability.

At the underside of bracket 23 is a bearing strap 36 adapted to pivotally mount bracket 23 to the cylindrical end 27 of cradle frame 16. The strap 36 wraps about the cylindrical end 27 to permit pivotal movement of bracket 23 about an axis within a vertical plane longitudinally parallel to the centerline of framework 10. The transverse position of strap 26 along the length of bracket 23 can be adjusted by means of mounting bolts 28 which are received through transverse slots 30 extending along the upper surface of bracket 23.

Each chine roller assembly 22 on the intermediate cradle frame 20 are substantially identical in structure to the transom roller assembly 18 described above. However, they may employ rolls31 of smaller diameter than the previously described rolls 26. Because the transom rollsare subjected to the greatest transverse forces due to the hull strakes at a time when the boat keel is not substantially engaged by keel rolls, I have found it best to use particularly enlarged roll diameters for the rolls 26. An example of such rolls actually in use have an outer diameter of approximately 5 inches. The chine rolls 31 can be smaller, which permits greater economy in roll manufacture. However, the difference in radius between the radius of roll 31 and the axle on which they are mounted must also exceed the projection of the strakes outwardly from a boat hull.

FIG. 6 illustrates schematically the manner by which the present transom roller assembly 18 engages longitudinal strakes 32 along a typical deep-V hull 33. As the bow of the hull 33 is pulled between the transom roller assembly l8,they will pivot about the cylindrical ends of cradle frame 16 so that both rolls 26 at each side of the hull will come into rolling engagement with the hull surfaces. Because the strakes 32 diverge transversely along the forward length of the hull 33, it is necessary that the rolls 26 permit the strakes to ride over the rolls during longitudinal movement of the hull 33. The tapered ends of roll 26 permit such movement, which is facilitated by the relatively hard nature of the outer resilient surface of each roll 26.

It is important that each roll 26, 31 be rotated about a single transverse axis through its supporting axle, and not be permitted to wobble or to otherwise deviate from a fixed rolling path. I have found that such freedom in the rolls results in a tendency of the rolls to be wedged against the sides of the strake 32, which impedes or prevents the strakes from traversing the rolls. In addition, it is important that the brackets 23 be limited to pivotal movement about a single axis, again to prevent any deviation of the rolls from a true transverse position for simple rolling movement.

A particular trailer is set to receive a boat by adjustment of the various rolls along the length of framework 10. With respect to the present roll assembly, one should transversely position the transom roller assemblies 18 so as to straddle the strakes 32 when the boat is fully loaded on the trailer. The chine roller assemblies 22 should straddle strakes 32 or locate between strakes 32. Such adjustment is effected by moving brackets 23 transversely after loosening the bolts 28. After the roller assemblies 18, 22 have been set for a particular boat, they can remain permanently in such condition and the loaded boat will be seated properly between the respective rolls. This adjustment eliminates the transport of a boat with a strake 32 resting on any of 5 the rolls.

Various modifications might be made in the apparatus without deviating from the basic concept of the novel rolls and roller assembly described above. Therefore, only the following claims are intended to restrict the invention described herein.

Having thus described my invention, I claim:

1. In a boat trailer for molded boat hulls having protruding longitudinal strakes which diverge transversely from front to back, said trailer comprising:

a longitudinal wheeled framework;

a roller support frame mounted to said framework;

and a transverse straight axle mounted to said frame;

the improvement comprising:

a pair of enlarged rollers rotatably mounted on said axle at opposite ends thereof and limited to rotational motion about the axis of said axle, said rollers being spaced apart along said axle;

each of said rollers having cylindrical side surfaces generated about an axis coaxial with the axle axis and end surfaces tapered outwardly along conical paths, the difference in radius between the rollers and axle being greater than the projection of the strakes outward of the boat hull;

the axle being exposed between said rollers along a length sufficient to receive a hull strake.

2. The apparatus as set out in claim 1 further comprising:

a transversely adjustable bracket assembly connecting said axle to said frame for varying the transverse location of the axle relative to said framework.

3. A roller assembly for boat trailers adapted to accomodate boat hulls having protruding longitudinal strakes which diverge transversely from front to back, said roller assembly comprising:

a transverse support bracket;

bearing means on said bracket for pivotal connection to a supporting member about an axis perpendicular to the bracket length;

astraight axle having a center axis, said axle being mounted along the top of said bracket with the axis thereof parallel to the bracket length;

a pair of oppositely facing identical rollers mounted on the respective ends of said axle about rotational axes coincident with the axle axis;

each roller including a center cylindrical section formed about its rotational axis and symmetrical tapered end surfaces in the form of conical surfaces centered along the rotational axis at the respective ends thereof;

said rollers being spaced apart along the axle by a distance sufficient to accommodate at least one of said strakes, and the difference in radius between the rollers and axle being greater than the projection of the strakes outward of the boat hull.

4. The assembly as set out in claim 3 wherein the outer surfaces of said rollers and axle are formed from hard rubber material.

5. The assembly as set out in claim 3 wherein the rollers are rotatably joumalled on the axle ends by bearings within the roller structure, the outer end of the axle being recessed inwardly of the outer end of each roller.

6. The assembly as set out in claim 3 wherein said bearing means is transversely adjustable relative to the bracket on which it is mounted, whereby the location of the pivotal connection of the bracket to a Supportin g member may be selectively varied along the length of the bracket. 

1. In a boat trailer for molded boat hulls having protruding longitudinal strakes which diverge transversely from front to back, said trailer comprising: a longitudinal wheeled framework; a roller support frame mounted to said framework; and a transverse straight axle mounted to said frame; the improvement comprising: a pair of enlarged rollers rotatably mounted on said axle at opposite ends thereof and limited to rotational motion about the axis of said axle, said rollers being spaced apart along said axle; each of said rollers having cylindrical side surfaces generated about an axis coaxial with the axle axis and end surfaces tapered outwardly along conical paths, the difference in radius between the rollers and axle being greater than the projection of thE strakes outward of the boat hull; the axle being exposed between said rollers along a length sufficient to receive a hull strake.
 2. The apparatus as set out in claim 1 further comprising: a transversely adjustable bracket assembly connecting said axle to said frame for varying the transverse location of the axle relative to said framework.
 3. A roller assembly for boat trailers adapted to accomodate boat hulls having protruding longitudinal strakes which diverge transversely from front to back, said roller assembly comprising: a transverse support bracket; bearing means on said bracket for pivotal connection to a supporting member about an axis perpendicular to the bracket length; a straight axle having a center axis, said axle being mounted along the top of said bracket with the axis thereof parallel to the bracket length; a pair of oppositely facing identical rollers mounted on the respective ends of said axle about rotational axes coincident with the axle axis; each roller including a center cylindrical section formed about its rotational axis and symmetrical tapered end surfaces in the form of conical surfaces centered along the rotational axis at the respective ends thereof; said rollers being spaced apart along the axle by a distance sufficient to accommodate at least one of said strakes, and the difference in radius between the rollers and axle being greater than the projection of the strakes outward of the boat hull.
 4. The assembly as set out in claim 3 wherein the outer surfaces of said rollers and axle are formed from hard rubber material.
 5. The assembly as set out in claim 3 wherein the rollers are rotatably journalled on the axle ends by bearings within the roller structure, the outer end of the axle being recessed inwardly of the outer end of each roller.
 6. The assembly as set out in claim 3 wherein said bearing means is transversely adjustable relative to the bracket on which it is mounted, whereby the location of the pivotal connection of the bracket to a supporting member may be selectively varied along the length of the bracket. 